Endurance Skating

Training, Racing & LCHF Fueling For Skating And Endurance Sports

The F.A.S.T.E.R. Study – Has High-Fat’s Moment Arrived?

Drs Jeff Volek & Steve Phinney are the pre-eminent names in the study of the LCHF diet for athletes – Phinney is the doyen who’s been researching this stuff for 30 years, despite vociferous criticism and being seen as a heretic from the mainstream, and for at least the last decade Jeff Volek has been working alongside him.

Between them they have authored the pioneering book The Art & Science Of Low Carbohydrate Performance, as well as it’s companion book the Art & Science of Low Carbohydrate Living. The A&SOLCP book is, for the moment, the definitive text on keto- and fat-adaptation for athletes.

More recently they have been conducting the FASTER Study (Fat Adapted Substrate oxidation in Trained Elite Runners) – this is absolutely ground-breaking stuff, putting into practice everything that they have learnt in all the time they have been researching LCHF in athletes, and (hopefully) being able to demonstrate the clear advantages that athletes who actively pursue a higher fat diet have been able to achieve… stuff that is often blogged about, but never funded in a proper well-designed study until now.

Endurance Planet recently scooped an interview with Jeff Volek & Zach Bitter (who should need no introduction if you read this blog) about the FASTER Study.  I absolutely love Endurance Planet… you should all listen to it, especially the weekly Ask The Coaches episodes, which are a goldmine of great knowledge and training advice.

More details on the FASTER study:


  • 10 elite fat-adapted athletes were each paired with an equivalent traditional high(er) carb athlete. The idea was for each subject to be tested against an equally matched athlete with the main difference being their diet composition.
  • Fat/Protein/Carb breakdown for the High Fat group was 70/20/10, compared to 25/15/60 for the high carb group
  • Testing protocol involved running 3hrs at 70% VO2max
  • Gaseous RQ measured during exercise, and before/after muscle biopsies taken (painful) to determine very precisely how much fat and how much carbohydrate was used during exercise
  • Many other biomarkers were recorded

Some of the preliminary results:

  • The high-fat group’s mean fat oxidation rate was triple that of the low-carb group. This is not surprising if you’re familiar with the literature, but will be hugely surprising if you’re not.
  • High fat group average 90% fat oxidation of total energy expenditure, absolute figure of 1.54g/min fat oxidation (92.4g/min)
  • Low fat group average 55-60% fat oxidation of total energy expenditure (they shifted to slightly higher fat after a period, although never as high as seen in the high fat group) 0.67g/min fat oxidation (40.2g/min)


Some notes –

Obviously the main eye-popping difference is that the high-fat group is able to oxidize 2.3 times as much fat as the high carb group – this directly translates into a lesser reliance on stored and exogenous carbohydrate sources during exercise.  Actually, I’m quite impressed that the high-carb group is still able to oxidize as much as 0.67g/min from fat (translating to roughly 60% of total energy expenditure once in a steady state) – they are still predominantly fat-fueled and have not yet reached their crossover point under this testing protocol. We know that fat-burning is also about stress, lifestyle and training, and being elite utrarunners, these guys are obviously doing a lot of stuff that promotes healthy fat-based metabolism. Conversely, some people are so carb-dependent that they don’t ever see a crossover point – they are burning predominantly carbs even at rest! These people tend to have health/weight and other metabolic issues.

However, 2.3 times more fax oxidation for the high-fat group is pretty spectacular whichever way you look at it.  In context, we’ve never seen a study that has so clearly shown how fat/carb mixture can be managed so successfully by actively pursuing a high fat diet. It shouldn’t come as a surprise that the body fuels itself primarily on what is most abundant in the diet.


What does 1.5g fat/minute for a fat-adapted athlete (the mean figure for the high-fat group) actually provide? Remember, there are 9 kcals in 1g of fat, so if we are burning 1.5g per minute, that is 810kcal/hour, or 900kcal/hr total if you include carb calories. Next time you’re in a gym, jump on a treadmill or an exercise bike, crank it up to 900cal/hr and you’ll see that it ain’t exactly a stroll in the park.


Volek says that while the group were obviously very fit runners, their VO2max numbers were not freakish, being in the 60-something range to produce this figure of 1.54gr/minute fat oxidation.  A individual with a higher outright VO2max will be able to oxidize even more – the highest individual in the FASTER study peaked out at 1.8g/min, and Volek theorizes that an individual who had a 90-something VO2max (these guys do exist) could get up to 2g/minute.


These fat oxidation figures are mind blowing when you consider that previously it was thought that 0.5g/minute was about the most that normal people could oxidize.  By extension, this old-world thinking perculates down into just about every piece of high-carb propaganda that you typically come across from the sports drink industry…. as you can see from this typical piece of misinformation…


“old style” thinking said that you can’t oxidize more than 35-40g fat/hr… http://secure.newsletters.co.uk/pponline/reports/carbohydrates.pdf

Of course, this was based off one single old study of test subjects none of whom were actively pursuing a high fat diet. The famous chart from that particular study is shown here….


The old study concluded human’s couldn’t oxidize more than 0.5g fat no matter how high your VO2max

The FASTER Study consigns that old paradigm to the waste bin. The next two charts are the money shots from the FASTER study, showing how much less reliant on carbs the high fat athletes are:


Maximal fax oxidation of high fat vs high carb

Faster Study results

substrate usage of high fat vs high carb

The FASTER Study has yet to officially publish its results – so everything you hear about it at the moment is very much unofficial.

As well as headline fat oxidation during exercise, the study also recorded alll sorts of biomarkers and will also have things to say about how the two groups fared in terms inflammation and recovery.

From the noises being made, and the fact that Dr Volek is willing to give “sneek preview” of some of the data, we can expect that there’s a lot of other good stuff that they will be able to conclude from the results of the study.

But why wait? If you’ve been reading blog like this, listening to great podcasts like Endurance Planet, then you already know what the study results are going to say.  Get ahead of the pack and get fat-adapted.


more reading….




5 comments on “The F.A.S.T.E.R. Study – Has High-Fat’s Moment Arrived?

  1. Ru El
    March 14, 2015

    Thanks for posting and sharing. We’ve heard about the FASTER study awhile from athletes participants like Ben and Zach. Zach had shared bits of his results on his blog earlier on. Ben described multiple times about his experience on podcasts as well. We’ve been clamoring for more from the study. I have a bit to catch up on with EP podcast. Cheers!

    Liked by 1 person

  2. Van
    March 14, 2015

    Thanks Ru El! Yes, the actual testing was conducted early last year I believe. Steve Phinney has alluded to the results in some of his recent talks that are on Youtube.
    But you know they say that the research always lags what is happening in the field – and as groundbreaking as it is in research terms, we already know that there is a groundswell of athletes (and not just endurance athletes) already using high fat diets!


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  5. Van
    November 12, 2015

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This entry was posted on March 13, 2015 by in Nutrition, Science and tagged , , , , .

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